Since we are adding a 5% each year, we will proceed as follows, we determine the final percentages and start from "the end to the beginning":
[tex]y_4=50000-50000\cdot0.05\Rightarrow y_4=47500[/tex]Then:
[tex]y_3=47500-47500\cdot0.05\Rightarrow y_3=45125[/tex]And for year two:
[tex]y_2=45125-45125\cdot0.05\Rightarrow y_2=42868.75[/tex]Finally, for the starting year, we will have:
[tex]y_1=42868.75-42868.75\cdot0.05\Rightarrow y_1=40725.3125[/tex]oneedFrom this, we have that the amount of money we need to have in order to get $50 000 in the interest of 5% is approximately $40 725.31.